1. Field of the Invention
The present invention relates to a method of designing a tire, a method of designing a vulcanizing mold for a tire, a method of making a vulcanizing mold for a tire, a method of manufacturing a pneumatic tire, and a recording medium with a tire designing program recorded thereon. Specifically, the present invention relates to a tire designing method for designing a tire while considering the performance of a pneumatic tire used in an automobile or the like, particularly the tire performance, such as drainage performance, on-snow performance, and noise performance, in the presence of a fluid, a method of designing a vulcanizing mold for a tire which vulcanizing mold is for manufacturing a tire, a method of making a vulcanizing mold for a tire, a method of manufacturing a pneumatic tire, and a recording medium with a tire designing program recorded thereon.
2. Description of the Related Art
Conventionally, in the development of a pneumatic tire, tire performance is obtained by conducting performance tests by actually designing and manufacturing a tire and mounting it on an automobile, and if the results of the performance tests are unsatisfactory, the procedure is repeated starting from the design and manufacture. In recent years, owing to the development of numerical analysis techniques such as the finite element method and the development of the computer environment, it has become possible to estimate by computers the state of inflation of the tire with internal pressure and the state of load at a time when the tire is not rolling, and it has become possible to make a number of performance estimates based on this estimation. However, it has hitherto been impossible to compute those tire performances such as drainage performance, on-snow performance, and noise performance, that are determined by the behavior of a fluid. For this reason, the present situation is such that it is impossible to conduct the estimation of tire performance and efficiently perform tire development.
A technical document is known in which an attempt was made to analyze the drainage performance, particularly hydroplaning, of a tire with respect to a smooth tire (grooveless tire) and a tire provided with only circumferential grooves (xe2x80x9cTire Science and Technology, TSTCA, Vol. 25, No. 4, October-December, 1997, pp. 265-287xe2x80x9d).
However, in this conventional technical document, analysis is attempted with respect to only the smooth tire and the tire provided with only circumferential grooves, and no reference is made to tires with patterns having inclined grooves intersecting the circumferential direction of the tire, which largely contribute to the drainage performance in actual tires. Further, how the fluid during ground contact and rolling of the tire can be brought close to a flowing state and how transient analysis can be made possible is not addressed. Namely, no consideration has been given to an analysis in which an actual tire is assumed to be in an actual environment.
In view of the above-described facts, an object of the present invention is to obtain a method of designing a tire which is capable of making tire development efficient while considering performance, such as drainage performance, on-snow performance, and noise performance, of a tire actually used in the presence of a fluid, and is capable of obtaining a tire exhibiting satisfactory performance, a method of designing a vulcanizing mold for a tire, a method of making a vulcanizing mold for a tire, a method of manufacturing a pneumatic tire, and a recording medium (recordable/readable medium) with a tire designing program recorded thereon.
To attain the above object, in the present invention, performance, such as drainage performance, on-snow performance, and noise performance, of a tire actually used in the presence of a fluid is estimated. In particular, the fluid at the time of ground contact and rolling of the tire is brought close to a flowing state, and transient analysis is made possible. In addition, the development of the tire is made efficient, and the provision of a tire having satisfactory performance is facilitated.
Specifically, the method of designing a tire according to a first aspect of the invention comprises the steps of: (a) determining a tire model having no pattern configuration to which deformation can be imparted by at least one of ground contact and rolling, and a fluid model at least partially filled with a fluid which comes into contact with at least a portion of the tire model; (b) performing deformation calculation of the tire model based on the at least one of ground contact and rolling of the tire model; (c) performing fluid calculation of the fluid model based on the at least one of ground contact and rolling of the tire model; and (d) estimating behavior of the fluid model due to the at least one of ground contact and rolling of the tire model, and designing a pattern configuration for the tire model based on the behavior of the fluid model.
A second aspect of the invention is the method according to the first aspect, wherein, in the step (d), at least one streamline of the fluid model, as the behavior of the fluid model, is estimated, and at least one groove is formed on the tire model on the basis of a direction in which the streamline extends.
A third aspect of the present invention is the method according to the first aspect, wherein, in the step (d), a pressure distribution of the fluid model, as the behavior of the fluid model, is estimated, and at least one groove is formed on the tire model on the basis of the pressure distribution of the fluid model.
A fourth aspect of the present invention is the method according to the third aspect, wherein, in the step (d), at least one substantially straight groove is formed on the tire model in a circumferential direction thereof on the basis of the pressure distribution of the fluid model.
A fifth aspect of the present invention is the method according to the third aspect, wherein, in the step (d), a volume of the groove formed on the tire model is determined on the basis of the pressure distribution of the fluid model.
A sixth aspect of the present invention is the method according to the first aspect, wherein re-execution of the steps (b), (c) and (d) is done using the tire model having the pattern configuration designed in the step (d), and at least one of a notch and a sipe is formed on the tire model on the basis of the behavior of the fluid model estimated in the re-execution of the steps (b), (c) and (d).
A seventh aspect of the invention is the method according to the first aspect further comprising the steps of: (1) identifying a boundary surface between the tire model after the deformation calculation in the step (b) and the fluid model after the fluid calculation in the step (c); (2) imparting a boundary condition, relating to the identified boundary surface, to the tire model and the fluid model; and (3) performing deformation calculation of the tire model and fluid calculation of the fluid model; wherein the steps of identifying a boundary surface, imparting a boundary condition, and performing deformation calculation of the tire model and fluid calculation of the fluid model are repeated until the fluid model assumes a state of pseudo flow.
An eighth aspect of the invention is the method according to the seventh aspect, further comprising the step of determining a physical quantity present in at least one of the tire model and the fluid model obtained in the steps (1) to (3), wherein in the step (d), the behavior of the fluid model is estimated on the basis of the physical quantity.
A ninth aspect of the invention is the method according to the first aspect, wherein the step (a) further includes determining a road surface model in contact with the fluid model.
A tenth aspect of the invention is the method according to the first aspect, wherein, in the step (b), the deformation calculation is repeated for no more than a predetermined time duration.
An eleventh aspect of the present invention is the method according to the tenth aspect, wherein the predetermined time duration is no more than 10 msec.
A twelfth aspect of the present invention is the method according to the first aspect, wherein, in the step (c), the fluid calculation is repeated for no more than a predetermined time duration.
A thirteenth aspect of the present invention is the method according to the twelfth aspect, wherein the predetermined time duration is no more than 10 msec.
A fourteenth aspect of the present invention is the method according to the seventh aspect, wherein the steps (1)-(3) are carried out within a predetermined time duration.
A fifteenth aspect of the invention is the method according to the fourteenth aspect, wherein the predetermined time duration is no more than 10 msec.
A sixteenth aspect of the invention is the method according to the first aspect, wherein if the tire model is a rolling model, the step (a) includes providing an internal pressure to the tire model, applying load to the tire model, and imparting at least one of a roational displacement, a speed, and a straight advance displacement.
A seventeenth aspect of the invention is the method according to the first aspect, wherein if the tire model is a rolling model, the step (a) includes imparting to the fluid model influx and efflux conditions such that fluid can flow out from a top surface of the fluid model and does not flow into or flow out of surfaces other than the top surface of the fluid model.
An eighteenth aspect of the invention is the method according to the first aspect, wherein if the tire model is a nonrolling model, the step (a) includes providing an internal pressure to the tire model, and applying load to the tire model.
A nineteenth aspect of the invention is the method according to the first aspect, wherein if the tire model is a nonrolling model, the step (a) includes imparting to the fluid model influx and efflux conditions such that fluid flows into a front surface of the fluid model at a predetermined velocity, the fluid can flow from a rear surface of the fluid model and a top surface of the fluid model, and the fluid does not flow into or flow out of side surfaces of the fluid model and a lower surface of the fluid model.
A twentieth aspect of the invention is the method according to the ninth aspect, wherein, determining a road surface model includes selecting a coefficient of friction xcexc for road surface condition representing at least one of road surface conditions including dry, wet, icy, snowy, and unpaved conditions.
A twenty-first aspect of the invention is the method according to the seventh aspect, wherein in the steps (1) to (3), an interfering portion is generated between the tire model and the fluid model, the interfering portion is identified, and the fluid model is divided with a boundary surface which is a surface of the tire model in the interfering portion, thereby fluid elements of the fluid model are divided.
A twenty-second aspect of the invention is the method according to the eighth aspect, wherein the fluid model contains at least water, and the physical quantity is at least one of ground contact area and ground contact pressure of the tire model in order for that the behavior of the fluid model is estimated.
A twenty-third aspect of the invention is the method according to the eighth aspect, wherein the fluid model contains at least water, and the physical quantity is at least one of pressure, flow volume, and flow velocity of the fluid model in order for that the behavior of the fluid model is estimated.
A twenty-fourth aspect of the invention is the method according to the eighth aspect, wherein the fluid model contains at least one of water and snow, and the physical quantity is at least one of ground contact area, ground contact pressure, and shearing force of the tire model on at least one of an icy road surface and a snowy road surface in order for that the behavior of the fluid model is estimated.
A twenty-fifth aspect of the invention is the method according to the eighth aspect, wherein the fluid model contains at least one of water and snow, and the physical quantity is at least one of pressure, flow volume, and flow velocity of the fluid model on at least one of an icy road surface and a snowy road surface in order for that the behavior of the fluid model is estimated.
A twenty-sixth aspect of the invention is the method according to the eighth aspect, wherein the fluid model contains at least air, and the physical quantity is at least one of pressure, flow volume, flow velocity, energy, and energy density in order for that the behavior of the fluid model is estimated.
A twenty-seventh aspect of the present invention is a method of designing a vulcanizing mold for a tire, comprising the steps of: (a) determining a tire model having no pattern configuration to which deformation can be imparted by at least one of ground contact and rolling, and a fluid model at least partially filled with a fluid which comes into contact with at least a portion of the tire model; (b) performing deformation calculation of the tire model based on the at least one of ground contact and rolling of the tire model; (c) performing fluid calculation of the fluid model based on the at least one of ground contact and rolling of the tire model; (d) identifying a boundary surface between the tire model after the deformation calculation in the step (b) and the fluid model after the fluid calculation in the step (c); (e) imparting a boundary condition, relating to the identified boundary surface, to the tire model and the fluid model; (f) performing deformation calculation of the tire model and fluid calculation of the fluid model, wherein the steps of identifying a boundary surface, imparting a boundary condition, and performing deformation calculation of the tire model and fluid calculation of the fluid model are repeated until the fluid model assumes a state of pseudo flow; (g) determining a physical quantity present in at least one of the tire model and the fluid model in the steps (d)-(f); (h) estimating the behavior of the fluid model on the basis of the physical quantity; and (i) designing a vulcanizing mold for the tire on the basis of the tire model which has a pattern configuration designed on the basis of the behavior of the fluid model.
A twenty-eighth aspect of the present invention is a method of making a vulcanizing mold for a tire, wherein a vulcanizing mold for a pneumatic tire is designed by the method of designing a vulcanizing mold for a tire comprising the steps of: (a) determining a tire model having no pattern configuration to which deformation can be imparted by at least one of ground contact and rolling, and a fluid model at least partially filled with a fluid which comes into contact with at least a portion of the tire model; (b) performing deformation calculation of the tire model based on the at least one of ground contact and rolling of the tire model; (c) performing fluid calculation of the fluid model based on the at least one of ground contact and rolling of the tire model; (d) identifying a boundary surface between the tire model after the deformation calculation in the step (b) and the fluid model after the fluid calculation in the step (c); (e) imparting a boundary condition, relating to the identified boundary surface, to the tire model and the fluid model; (f) performing deformation calculation of the tire model and fluid calculation of the fluid model, wherein the steps of identifying a boundary surface, imparting a boundary condition, and performing deformation calculation of the tire model and fluid calculation of the fluid model are repeated until the fluid model assumes a state of pseudo flow; (g) determining a physical quantity present in at least one of the tire model and the fluid model in the steps (d)-(f); (h) estimating the behavior of the fluid model on the basis of the physical quantity; and (i) designing a vulcanizing mold for the tire on the basis of the tire model which has a pattern configuration designed on the basis of the behavior of the fluid model.
A twenty-ninth aspect of the present invention is a method of manufacturing a pneumatic tire, wherein a vulcanizing mold for a pneumatic tire is made by the method of designing a vulcanizing mold for a tire comprising the steps of: (a) determining a tire model having no pattern configuration to which deformation can be imparted by at least one of ground contact and rolling, and a fluid model at least partially filled with a fluid which comes into contact with at least a portion of the tire model; (b) performing deformation calculation of the tire model based on the at least one of ground contact and rolling of the tire model; (c) performing fluid calculation of the fluid model based on the at least one of ground contact and rolling of the tire model; (d) identifying a boundary surface between the tire model after the deformation calculation in the step (b) and the fluid model after the fluid calculation in the step (c); (e) imparting a boundary condition, relating to the identified boundary surface, to the tire model and the fluid model; (f) performing deformation calculation of the tire model and fluid calculation of the fluid model, wherein the steps of identifying a boundary surface, imparting a boundary condition, and performing deformation calculation of the tire model and fluid calculation of the fluid model are repeated until the fluid model assumes a state of pseudo flow; (g) determining a physical quantity present in at least one of the tire model and the fluid model in the steps (d)-(f); (h) estimating the behavior of the fluid model on the basis of the physical quantity; and (i) designing a vulcanizing mold for the tire on the basis of the tire model which has a pattern configuration designed on the basis of the behavior of the fluid model.
A thirtieth aspect of the invention is a method of manufacturing a pneumatic tire comprising the steps of: (a) determining a tire model having no pattern configuration to which deformation can be imparted by at least one of ground contact and rolling, and a fluid model at least partially filled with a fluid which comes into contact with at least a portion of the tire model; (b) performing deformation calculation of the tire model based on the at least one of ground contact and rolling of the tire model; (c) performing fluid calculation of the fluid model based on the at least one of ground contact and rolling of the tire model; (d) identifying a boundary surface between the tire model after the deformation calculation in the step (b) and the fluid model after the fluid calculation in the step (c); (e) imparting a boundary condition, relating to the identified boundary surface, to the tire model and the fluid model; (f) performing deformation calculation of the tire model and fluid calculation of the fluid model, wherein the steps of identifying a boundary surface, imparting a boundary condition, and performing deformation calculation of the tire model and fluid calculation of the fluid model are repeated until the fluid model assumes a state of pseudo flow; (g) determining a physical quantity present in at least one of the tire model and the fluid model in the steps (d)-(f); (h) estimating the behavior of the fluid model on the basis of the physical quantity; and (i) designing a vulcanizing mold for the tire on the basis of the tire model which has a pattern configuration designed on the basis of the behavior of the fluid model.
A thirty-first aspect of the present invention is a recording medium with a tire designing program recorded thereon for designing a tire by a computer, wherein the tire designing program comprises the steps of: (a) determining a tire model having no pattern configuration to which deformation can be imparted by at least one of ground contact and rolling, and a fluid model at least partially filled with a fluid which comes into contact with at least a portion of the tire model; (b) performing deformation calculation of the tire model based on the at least one of ground contact and rolling of the tire model; (c) performing fluid calculation of the fluid model based on the at least one of ground contact and rolling of the tire model; (d) identifying a boundary surface between the tire model after the deformation calculation in the step (b) and the fluid model after the fluid calculation in the step (c); (e) imparting a boundary condition, relating to the identified boundary surface, to the tire model and the fluid model; (f) performing deformation calculation of the tire model and fluid calculation of the fluid model, wherein the steps of identifying a boundary surface, imparting a boundary condition, and performing deformation calculation of the tire model and fluid calculation of the fluid model are repeated until the fluid model assumes a state of pseudo flow; (g) determining a physical quantity present in at least one of the tire model and the fluid model in the steps (d)-(f); (h) estimating the behavior of the fluid model on the basis of the physical quantity; and (i) designing a vulcanizing mold for the tire on the basis of the tire model which has a pattern configuration designed on the basis of the behavior of the fluid model.
A thirty-second aspect of the invention is the method according to the second aspect, wherein in the step (d), at least one groove is formed at a portion on the tire model which portion corresponds to a higher fluid-pressure portion in the fluid model.
A thirty-third aspect of the invention is the method according to the third aspect, wherein, in the step (d), at least one groove is formed at a portion on the tire model which portion corresponds to a higher fluid-pressure portion in the fluid model.
A thirty-fourth aspect of the invention is the method according to the fourth aspect, wherein, in the step (d), at least one substantially straight groove is formed at a portion on the tire model which portion corresponds to a higher fluid-pressure portion in the fluid model.
A thirty-fifth aspect of the invention is the method according to the fifth aspect, wherein, in the step (d), a large-volume groove is formed at a portion on the tire model which portion corresponds to a higher fluid-pressure portion in the fluid model.
A thirty-sixth aspect of the invention is the method according to the sixth aspect, wherein at least one of the notch and the sipe is formed at a portion on the tire model which portion corresponds to a higher fluid-pressure portion in the fluid model.
In the present invention, first, a draft design of the tire is incorporated into a model in numerical analysis so as to estimate the performance of a tire to be evaluated (such as the change of the shape, structure, materials, and pattern of the tire). Namely, a tire model which can be numerically analyzed (a numerical analysis model) is constructed. In the present invention, a model of a tire having no patterns, i.e., a so-called smooth tire, is used as the tire model. Further, modeling of a fluid and a road surface relating to the targeted performance is carried out to construct a fluid model and a road surface model (numerical analysis models), numerical analysis which simultaneously takes into consideration the tire, the fluid, and the road surface is carried out, and the targeted performance is numerically estimated. The acceptability of the draft design of the tire is determined from the result of this estimation, and if the result is favorable, the draft design is adopted, or a tire of this draft design is manufactured, and the performance evaluation is conducted. If these results up to this stage were satisfactory, the draft design was adopted. If the estimated performance (or actually measured performance) based on the draft design was unsatisfactory, a part or the whole of the draft design might be corrected, and the procedures were carried out again starting with the construction of the numerical analysis models. In this procedures, the number of times in manufacturing tires and the tire performance evaluations can be minimized, so that the development of the tire can be made more efficient.
Accordingly, to undertake the development of the tire based on the estimation of performance, a numerical analysis model for tire performance estimation which is efficient and highly accurate is essential. Therefore, in the present invention, in order to estimate the tire performance, in step (a), a tire model having no pattern configuration and to which deformation can be imparted by at least one of ground contact and rolling, as well as a fluid model which is filled with a fluid and comes into contact with at least a portion of the tire model, are determined. Further, a road surface model can be determined. In step (b), deformation calculation of the tire model is executed and, in step (c), fluid calculation of the fluid model is executed. Further, the following substeps (1) to (3) are repeated until the fluid model assumes a state of pseudo flow: (1) a boundary surface between the tire model after the deformation calculation in step (b) and the fluid model after the fluid calculation in step (c) is identified; (2) a boundary condition relating to the identified boundary surface is imparted to the tire model and the fluid model; and (3) the deformation calculation of the tire model and the fluid calculation of the fluid model are executed. A physical quantity present in at least one of the tire model and the fluid model in steps (1)-(3) is determined and, in step (d), the behavior of the fluid model is estimated on the basis of the physical quantity. Examples of the behavior of the fluid model include streamlines (flow lines) such as ridge lines formed at the time of deformation of the fluid and traces (tracks) formed when a part of the fluid splashes out and is scattered. In step (d), streamlines, for example, are estimated. Also in step (d), a pattern configuration of the tire model is designed on the basis of the behavior of the fluid model.
In this step (d), grooves which are formed along the streamlines estimated in this step (d) can be designed in the pattern. By designing grooves in this manner, passages can be formed on the tire model in accordance with the directions in which the fluid moves or with the amount of the fluid.
In step (d), grooves can be formed in the directions in which the streamlines of the entire fluid model extend. Moreover, in step (d), grooves can be formed at portions where pressure of the fluid model is high. Further, in step (d), substantially straight (linear) groove(s) can be formed along the circumferential direction of the tire at portions where pressure of the fluid model is high. Furthermore, in step (d), grooves can be formed at portions where pressure of the fluid model is high, the volume of which grooves is larger than that of grooves formed at other portions. Moreover, in step (d), the fluid calculation can further be executed by using the tire model with the designed pattern, and at least one of a notch and a sipe can further be formed at portions where pressure of the fluid model is high.
It is also possible that the above-described method of designing a tire excludes repeating the following substeps until the fluid model assumes a state of pseudo flow: (1) a boundary surface between the tire model after the deformation calculation in step (b) and the fluid model after the fluid calculation in step (c) is identified; (2) a boundary condition relating to the identified boundary surface is imparted to the tire model and the fluid model; and (3) the deformation calculation of the tire model and the fluid calculation of the fluid model are executed.
The method of designing a tire without determining a physical quantity present in at least one of the tire model and the fluid model is also possible. Accordingly, the method of designing a tire without estimating the behavior of the fluid model on the basis of the physical quantity is also possible.
By designing a tire in this manner, it is possible to contribute to the design of the tire while taking into consideration the flow of the fluid around the tire and estimating the smoothness of flow, occurrence of the disturbance, and the tire performance.
In step (b), deformation calculation of the tire model at a time when deformation is imparted thereto by at least one of ground contact and rolling of the tire model can be executed. In this case, at least one of ground contact and rolling may be set as the input to the tire model.
Further, when a boundary condition relating to the recognized boundary surface is imparted to the tire model and the fluid model, the fluid model may be determined in such a manner that the fluid is present on the road surface model side relative to the boundary surface.
It should be noted that at least one of the deformation calculation of the tire model and the fluid calculation may be repeatedly performed. The predetermined time duration (the elapsed time) during which the deformation calculation is repeatedly performed may be 10 msec or less, preferably 1 msec or less, and more preferably 1 xcexcxc2x7sec or less. Further, the fixed time duration (the elapsed time) during which the fluid calculation is repeatedly performed may be 10 msec or less, preferably 1 msec or less, and more preferably 1 xcexcxc2x7sec or less. If this time duration (elapsed time) is too long, the fluid in the fluid model fails to assume a state of pseudo flow suitable for the behavior of the tire, and the accuracy as a numerical model deteriorates. For this reason, it is necessary to use an appropriate value as the elapsed time.
In addition, calculation, until the fluid model assumes the state of pseudo flow, may also be performed repeatedly. In this calculation, 10 msec or less may be used as the predetermined time duration (the elapsed time) during which the repeated calculation is performed. Preferably, it is possible to use 1 msec or less, and more preferably 1 xcexcxc2x7sec or less.
The aforementioned tire model may have a pattern partly. Further, as for the road surface model, an actual road surface condition can be reproduced by selecting a coefficient of friction xcexc representing a road surface condition of dry, wet, icy, snowy, unpaved or other conditions in accordance with the road surface condition.
When the boundary condition is imparted, it is important that the portion of the fluid model which is in contact with the surface of the tire model be recognized as the boundary surface of the fluid. However, if the very fine elements making up the fluid model are always made sufficiently small with respect to the tire model, and the number of constituent elements of the fluid model hence increases, an increase in the calculation time results, which entails difficulty. Accordingly, it is preferable to prevent an increase in the calculation time by making the very fine elements making up the fluid model large to a certain measure. At the same time, it is preferable to generate (overlap) an interfering portion between the tire model and the fluid model, identify (recognize) the interfering portion, and divide the fluid model with the surface of the tire model as a boundary surface, so as to allow the boundary surface between the tire model and the fluid model to be identified with high accuracy.
Further, if the fluid model contains at least water, and the ground contact area and ground contact pressure of the tire model are used as the physical quantity, it is possible to estimate the wet performance of the tire. Furthermore, if the fluid model contains at least water, and the pressure, flow volume, and flow velocity of the fluid model are used as the physical quantity, it is possible to estimate the behavior of the fluid model.
Moreover, if the fluid model contains at least one of water and snow, and at least one of the ground contact area, ground contact pressure, and shearing force of the tire model on at least one of an icy road surface and a snowy road surface is used as the physical quantity, it is possible to estimate the on-ice and on-snow performance of the tire. In addition, if the fluid model contains at least one of water and snow, and at least one of the pressure, flow volume, and flow velocity of the fluid model on at least one of an icy road surface and a snowy road surface is used as the physical quantity, it is possible to estimate the behavior of the fluid model with the on-ice and on-snow performance of the tire taken into consideration.
Further, if the fluid model contains at least air, and the pressure, flow volume, flow velocity, energy, and energy density of the fluid model is used as the physical quantity, it is possible to estimate the behavior of the fluid model with the noise performance of the tire taken into consideration.
Further, in a case where a tire vulcanizing mold for manufacturing a tire is designed, if the following steps are taken which include: (a) determining a tire model having no pattern configuration to which deformation can be imparted by at least one of ground contact and rolling, and a fluid model at least partially filled with a fluid which comes into contact with at least a portion of the tire model; (b) performing deformation calculation of the tire model based on the at least one of ground contact and rolling of the tire model; (c) performing fluid calculation of the fluid model based on the at least one of ground contact and rolling of the tire model; (d) identifying a boundary surface between the tire model after the deformation calculation in the step (b) and the fluid model after the fluid calculation in the step (c); (e) imparting a boundary condition, relating to the identified boundary surface, to the tire model and the fluid model; (f) performing deformation calculation of the tire model and fluid calculation of the fluid model, wherein the steps of identifying a boundary surface, imparting a boundary condition, and performing deformation calculation of the tire model and fluid calculation of the fluid model are repeated until the fluid model assumes a state of pseudo flow; (g) determining a physical quantity present in at least one of the tire model and the fluid model in the steps (d)-(f); (h) estimating the behavior of the fluid model on the basis of the physical quantity; and (i) designing a vulcanizing mold for the tire on the basis of the tire model which has a pattern configuration designed on the basis of the behavior of the fluid model, then it is possible to evaluate the flow of the fluid around the tire to be manufactured and use this in designing of the mold for manufacturing a tire. That is, the mold is designed while estimating the smoothness of flow, the occurrence of disturbance, and the tire performance.
If the tire vulcanizing mold thus designed is made, the manufacture of the tire in which the estimated behavior of the fluid model is taken into consideration is facilitated. Further, if this tire vulcanizing mold is made, and the tire is manufactured by using it, it is possible to obtain a tire in which the evaluation of the flow of the fluid, the smoothness of the flow, the occurrence of disturbance, and the like have been taken into consideration.
Moreover, in a case where a tire is manufactured, if the following steps are provided which include: (a) determining a tire model having no pattern configuration to which deformation can be imparted by at least one of ground contact and rolling, and a fluid model at least partially filled with a fluid which comes into contact with at least a portion of the tire model; (b) performing deformation calculation of the tire model based on the at least one of ground contact and rolling of the tire model; (c) performing fluid calculation of the fluid model based on the at least one of ground contact and rolling of the tire model; (d) identifying a boundary surface between the tire model after the deformation calculation in the step (b) and the fluid model after the fluid calculation in the step (c); (e) imparting a boundary condition, relating to the identified boundary surface, to the tire model and the fluid model; (f) performing deformation calculation of the tire model and fluid calculation of the fluid model, wherein the steps of identifying a boundary surface, imparting a boundary condition, and performing deformation calculation of the tire model and fluid calculation of the fluid model are repeated until the fluid model assumes a state of pseudo flow; (g) determining a physical quantity present in at least one of the tire model and the fluid model in the steps (d)-(f); (h) estimating the behavior of the fluid model on the basis of the physical quantity; and (i) designing a vulcanizing mold for the tire on the basis of the tire model which has a pattern configuration designed on the basis of the behavior of the fluid model, then it is possible to obtain a tire in which the evaluation of the flow of the fluid, the smoothness of the flow, the occurrence of disturbance, and the like have been taken into consideration.
Further, in a case where a tire is designed by a computer, if a tire designing program which includes the following steps is stored in a storage medium and is executed, and if data is collected: (a) determining a tire model having no pattern configuration to which deformation can be imparted by at least one of ground contact and rolling, and a fluid model at least partially filled with a fluid which comes into contact with at least a portion of the tire model; (b) performing deformation calculation of the tire model based on the at least one of ground contact and rolling of the tire model; (c) performing fluid calculation of the fluid model based on the at least one of ground contact and rolling of the tire model; (d) identifying a boundary surface between the tire model after the deformation calculation in the step (b) and the fluid model after the fluid calculation in the step (c); (e) imparting a boundary condition, relating to the identified boundary surface, to the tire model and the fluid model; (f) performing deformation calculation of the tire model and fluid calculation of the fluid model, wherein the steps of identifying a boundary surface, imparting a boundary condition, and performing deformation calculation of the tire model and fluid calculation of the fluid model are repeated until the fluid model assumes a state of pseudo flow; (g) determining a physical quantity present in at least one of the tire model and the fluid model in the steps (d)-(f); (h) estimating the behavior of the fluid model on the basis of the physical quantity; and (i) designing a vulcanizing mold for the tire on the basis of the tire model which has a pattern configuration designed on the basis of the behavior of the fluid model, then it is possible to perform tire designing which reflects the behavior of the fluid.